The main advantages of hydropower are obvious. Of course, the main advantage of hydro resources is their renewability: the supply of water is practically inexhaustible. At the same time, hydro resources are significantly ahead in development of other types of renewable energy sources and are capable of providing energy big cities and entire regions.

In addition, this energy source can be used quite simply, as evidenced by the long history of hydropower. For example, hydroelectric power generators can be turned on or off depending on energy consumption.

At the same time, the issue of the influence of hydropower on environment. On the one hand, the operation of hydroelectric power plants does not lead to environmental pollution with harmful substances, unlike CO 2 emissions produced by thermal power plants and possible accidents at nuclear power plants, which can lead to global catastrophic consequences.

But at the same time, the formation of reservoirs requires the flooding of large areas, often fertile, and this causes negative changes in nature. Dams often block the way for fish to spawning grounds, disrupt the natural flow of rivers, lead to the development of stagnant processes, reduce the ability to “self-purify”, and therefore dramatically change the quality of water.

The cost of energy produced at hydroelectric power plants is much lower than at nuclear and thermal power plants, and they are able to quickly reach operating power output mode after switching on, but their construction is more expensive.

Modern technologies for the production of hydroelectric power make it possible to obtain fairly high efficiency. Sometimes it is twice as high as that of conventional thermal power plants. In many ways, this efficiency is ensured by the features of the equipment of hydroelectric power plants. It is very reliable and easy to use.

In addition, all equipment used has one more important advantage. This long term service, which is explained by the lack of heat during the production process. And indeed, there is no need to change equipment often; breakdowns are extremely rare. The minimum service life of a hydroelectric power station is about fifty years. And in the vastness of the former Soviet Union Stations built in the twenties or thirties of the last century operate successfully. Hydroelectric power plants are controlled through a central hub and as a result, in most cases, have a small staff.

Conclusion

hydroelectric power station turbine cost energy

The potential of hydropower can be determined by summing up all river flows existing on the planet. Calculations have shown that the global potential is fifty billion kilowatts per year. But this very impressive figure is only a quarter of the amount of precipitation that falls annually throughout the world.

Taking into account the conditions of each specific region and the state of the world's rivers, the actual potential of water resources ranges from two to three billion kilowatts. These figures correspond to an annual energy production of 10,000 - 20,000 billion kilowatts per hour.

To understand the potential of hydropower expressed by these figures, the data obtained should be compared with the indicators of oil-fired thermal power plants. To generate this amount of electricity, oil-fired plants would need about forty million barrels of oil every day.

Without a doubt, hydropower in the future should not have a negative impact on the environment or reduce it to a minimum. At the same time, it is necessary to achieve maximum use of hydro resources.

Many experts understand this, and therefore the problem of preserving the natural environment during active hydraulic engineering construction is more relevant than ever. Currently, an accurate forecast of the possible consequences of the construction of hydraulic facilities is especially important. It should answer many questions regarding the possibility of mitigating and overcoming undesirable environmental situations that may arise during construction. In addition, a comparative assessment is necessary environmental efficiency future waterworks. True, the implementation of such plans is still far away, since today the development of methods for determining environmental energy potential is not being carried out.

ADVANTAGES OF HPP:

Flexibility

Hydropower is a flexible source of electricity because hydroelectric power plants can very quickly adapt to changing energy demands, increasing or decreasing electricity production. A hydraulic turbine has a startup time of the order of several minutes. It takes 60 to 90 seconds to bring the device from cold start to full load; this is much less than for gas turbines or steam plants. Electricity production can also be quickly reduced when there is excess power.

Ffestiniog power station can produce 360 ​​MW in 60 seconds

Low energy costs

The main advantage of hydroelectric power is the absence of fuel costs. The cost of operating a hydroelectric power plant is almost immune to increases in the cost of fossil fuels such as oil, natural gas or coal, and no import is required. The average cost of electricity from a hydroelectric power plant larger than 10 megawatts is 3 to 5 US cents per kilowatt-hour.

Hydroelectric power plants have a long service life, some hydroelectric power plants still provide electricity after 50-100 years of operation.

Operational maintenance costs are low, few people are required to control the operation of the hydroelectric power station.

The dam can be used for several purposes at once: accumulate water for hydroelectric power stations, protect territories from floods, create a reservoir.

Suitability for industrial use

While many hydroelectric power plants supply energy to the general electricity grid, some are created to serve specific industrial enterprises. For example, in New Zealand, a power station was built to supply electricity to the Tiwai Point aluminum smelter.

Reduced CO2 emissions

Hydroelectric power plants do not burn fossil fuels and do not directly produce carbon dioxide. Although some carbon dioxide is generated during the production and construction process of the project. According to a study by Paul Scherrer from the University of Stuttgart, hydropower produces the least carbon dioxide among other energy sources. Wind was in second place, nuclear energy was third, solar energy was in 4th place.

Other uses of the reservoir

Hydroelectric reservoirs often provide opportunities for water sports and become tourist attractions themselves. In some countries, aquaculture in reservoirs is common. Water from reservoirs can be used to irrigate crops, and fish can be raised in it. Dams also help prevent flooding.

DISADVANTAGES OF HYDRO POWER PLANT:

Ecosystem damage and land loss

The large reservoirs required to operate hydroelectric dams flood vast areas of land upstream from the dam, destroying forest valleys and swamps. Land loss is often compounded by habitat destruction in the surrounding areas occupied by the reservoir.
Hydroelectric power plants can lead to the destruction of ecosystems, as water passing through turbinescleared of natural sediments. Hydroelectric power stations on large rivers are especially dangerous, as they lead to serious changes in the environment.

The photo shows a reservoir resulting from the construction of a dam.

Siltation

When water flows, heavier particles float downstream.
This has Negative influence on dams and subsequently their power plants, especially on rivers or in catchments with a high degree of siltation. Silt can fill the reservoir and reduce its ability to control floods, causing additional horizontal pressure on the dam. Reducing the river bed can lead to a decrease in electricity production. In addition, even a hot summer or low rainfall can lead to a decrease in the river.

Methane emissions (from reservoirs)

Hydroelectric power plants in tropical regions have the greatest impact; reservoirs of power plants in tropical regions produce significant amounts of methane. This is due to the presence plant material in flooded areas, decaying anaerobically and producing methane and a greenhouse gas. According to the report of the World Commission on Dams, in cases where the reservoir is large compared to the generating capacity (less than 100 watts per square meter of surface area) and the forests in the area of ​​the reservoir have not been cleared. Then greenhouse gas emissions in the reservoir may be higher than those of a conventional thermal power plant.

One of the main advantages of small hydropower facilities is environmental Safety. During their construction and subsequent operation there are no harmful effects on the properties and quality of water. Reservoirs can be used for fishing activities and as sources of water supply for the population. However, in addition to this, micro and small hydroelectric power stations have many advantages. Modern stations are simple in design and fully automated, i.e. do not require human presence during operation. Produced by them electricity complies with GOST requirements for frequency and voltage, and the stations can operate in autonomous mode, i.e. outside the power grid of the power system of the region or region, and as part of this power grid. And the full service life of the station is at least 40 years (at least 5 years before overhaul). Well, and most importantly, small-scale energy facilities do not require the organization of large reservoirs with corresponding flooding of the territory and colossal material damage.

During the construction and operation of SHPPs, the natural landscape is preserved and there is virtually no load on the ecosystem. The advantages of small hydropower - compared to power plants using fossil fuels - also include: low cost of electricity and operating costs, relatively inexpensive replacement of equipment, longer service life of hydroelectric power plants (40-50 years), integrated use of water resources (electricity, water supply, reclamation, water protection, fisheries).

Many of the small hydroelectric power plants do not always provide guaranteed energy production, being seasonal power plants. In winter, their energy output drops sharply; snow cover and ice phenomena (ice and sludge), as well as summer low water and drying up of rivers, can completely stop their work. The seasonality of small hydroelectric power plants requires backup energy sources; a large number of them can lead to a loss of reliability of energy supply. Therefore, in many areas, the power of small hydroelectric power stations is considered not as the main one, but as a backup one.

Reservoirs of small hydroelectric power stations, especially in mountainous and foothill areas, have a very acute problem of their siltation and the associated problem of rising water levels, flooding and flooding, reducing the hydropower potential of rivers and generating electricity. It is known, for example, that the reservoir of the Zemonechal hydroelectric power station on the Kura River was silted by 60% within 5 years.

For fisheries, small hydroelectric dams are less dangerous than medium and large ones, which block the migration routes of anadromous and semi-anadromous fish and block spawning grounds. Although, in general, the creation of waterworks does not completely eliminate the damage to the fish stock on the main rivers, because river basin is a single ecological system and violations of its individual links inevitably affect the system as a whole.

IN Lately, as an alternative to classic medium-high-pressure dam hydroelectric power stations, low-pressure hydroelectric power stations operating on natural flow, which are quite widespread in Western Europe. Let's try to figure out what these hydroelectric power plants are and what their pros and cons are.

An example of a low-pressure run-of-the-river hydroelectric power plant is the Iffezheim hydroelectric power station on the Rhine, commissioned in 1978. Photo from here

The concept of a low-pressure run-of-river hydroelectric complex involves the creation of a hydroelectric power station on a flat river with a head of several meters, whose reservoir is usually located in the natural flood zone of the floodplain during heavy floods. Such waterworks have the following advantages:
* A small flood area, which usually does not include (or almost does not include) built-up lands. Consequently, no one needs to be resettled, and the impact on ecosystems is much less significant.
* It is much easier to integrate fish passages into low-pressure dams, and fish pass down through the turbines with less injury.

The Saratov hydroelectric power station is the lowest pressure one in the Volga-Kama cascade.

Now let's move on to the disadvantages:
* Such hydroelectric power stations form small reservoirs, suitable at best for daily flow regulation, or even operating on a watercourse. As a result, the production of such hydroelectric power plants is highly dependent on the season and weather conditions - during low-water periods it drops sharply.
* The efficiency of using runoff by such hydroelectric power plants is much less than by classical ones - not being able to accumulate runoff during high waters and floods, they are forced to empty a lot of water.
* Without a capacious reservoir, such hydroelectric systems cannot combat floods.
* From the point of view of navigation, the construction of several low-pressure hydroelectric complexes instead of one large one leads to an increase in locking time - instead of one lock, you need to go through several.
* Low-pressure hydroelectric power plants have a significantly higher unit cost (calculated per kW of power and kWh of generated electricity). The lower the pressure, the larger the dimensions and, accordingly, the metal consumption of the equipment; the inability to accumulate runoff in the reservoir leads to the need to create more powerful culvert structures; several sluices are more expensive than one, etc. For comparison, we can cite the low-pressure Polotsk hydroelectric power station in Belarus and the high-pressure Boguchanskaya hydroelectric power station. The first costs approximately $4,500 per kW, the second — about $1,000 per kW. The difference, as we see, is 4.5 times.

Hydroelectric power station Tucurui in Brazil. In the Amazonian jungle, as in the Siberian taiga, large hydroelectric power plants are more efficient.

Let's summarize. The advantages of low-pressure hydroelectric power plants are most significant in densely populated areas, where the high cost of land and a large amount of work to resettle people, remove structures and infrastructure make large hydroelectric power stations with large reservoirs are unacceptable. That is why low-pressure hydroelectric power plants are most widespread in Europe, where the population density is high and there are few own energy resources, which forces the use of all available hydro potential, albeit in expensive ways.
At the same time, in relatively sparsely populated regions, the advantages of large hydroelectric power stations are obvious - in fact, they are mainly being built there now all over the world (although the criteria for sparse population in different countries differ significantly; for China, with its billion-strong population, the resettlement of several tens of thousands of people is quite acceptable).

Low-pressure run-of-river hydroelectric power plants do not compete with medium- and high-pressure hydroelectric power stations - each type of hydroelectric power station has its own “ecological niche” in which they are most effective. And references to run-of-the-river hydroelectric power stations in Western Europe when discussing hydropower projects in Eastern Siberia are a comparison of the incomparable.

Like any other method of energy production, the use of small and mini hydroelectric power plants has both advantages and disadvantages.

Among economic, environmental and social benefits Small hydropower facilities can be named as follows. Their creation increases energy security region, ensures independence from fuel suppliers located in other regions, and saves scarce organic fuel. The construction of such an energy facility does not require large capital investments, large quantity energy-intensive building materials and significant labor costs, it pays off relatively quickly. It should be noted that the reconstruction of a previously decommissioned small hydroelectric power station will cost 1.5-2 times less. Small-scale energy facilities do not require the organization of large reservoirs with corresponding flooding of the territory and colossal material damage.

In addition, there are opportunities to reduce construction costs through unification and certification of equipment. Modern stations are simple in design and fully automated, i.e. do not require human presence during operation. The electric current they generate meets GOST requirements for frequency and voltage, and the stations can operate in autonomous mode, i.e. outside the power grid of the region's energy system, and as part of this power grid. And the full service life of the station is at least 40 years (at least 5 years before major repairs).

One of the main advantages of small hydropower facilities is environmental safety. During their construction and subsequent operation there are no harmful effects on the properties and quality of water. Reservoirs can be used for fishing activities and as sources of water supply for the population. In the process of generating electricity, the hydroelectric power station does not produce greenhouse gases and does not pollute the environment with combustion products and toxic waste, which meets the requirements of the Kyoto Protocol. Such objects do not cause induced seismicity and are relatively safe during the natural occurrence of earthquakes. They don't provide negative impact on the lifestyle of the population, on animal world and local microclimatic conditions.

A significant advantage is also the absence of disruption natural landscape and the environment during the construction process and at the operation stage, as well as practically complete independence from weather conditions. The supply of cheap electricity to the consumer is ensured at any time of the year. ??????????????? ????????????? ???????

In addition, mini-hydroelectric turbines can also be used as energy absorbers at differences in heights of drinking and other pipelines intended for pumping various types liquid products.

Possible problems associated with the creation and use of small hydropower facilities are less pronounced, but they should also be mentioned.

Like any localized energy source, in the case isolated application, a small hydropower facility is vulnerable from the point of view of failure, as a result of which consumers are left without power supply (the solution to the problem is the creation of joint or reserve generating capacities - a wind turbine, a cogeneration mini-boiler house using biofuel, a photovoltaic installation, etc.).

The most common type of accident at small hydropower facilities is the destruction of the dam and hydraulic units as a result of overflow over the dam crest due to an unexpected rise in the water level and failure of shut-off devices. In some cases, SHPPs contribute to the siltation of reservoirs and influence channel-forming processes.

There is a certain seasonality in electricity generation (noticeable declines in winter and summer period), leading to the fact that in some regions small hydropower is considered as reserve (duplicate) generating capacity.

Among the factors hindering the development of small hydropower, most experts cite incomplete awareness of potential users about the benefits of using small hydropower facilities; insufficient knowledge of the hydrological regime and flow volumes of small watercourses; low quality of existing methods, recommendations and SNiPs, which is the reason serious mistakes in calculations; lack of development of methods for assessing and predicting possible impacts on the environment and economic activity; weak production and repair base of enterprises producing hydropower equipment for small hydropower plants, and mass construction of small hydropower facilities is possible only if serial production equipment, abandonment of individual design and a qualitatively new approach to the reliability and cost of equipment - in comparison with old facilities decommissioned.

Energy sources

Energy sources for small hydropower are:

* small rivers, streams,

* natural differences in heights on lake spillways and on irrigation canals of irrigation systems,

* technological watercourses (industrial and sewer discharges),

* differences in heights of drinking pipelines, water treatment systems and other pipelines designed for pumping various types of liquid products.